<?php
$a=array(1,2,4,8);
$b=array(0,2,4,6,8,10);
//print_r(array_diff($a, $b));
//print_r(array_diff($b, $a));
//print_r(array_merge($a,$b));
echo count(array_merge(array_diff($a, $b),array_diff($b, $a)));
// Rpta-> 4
?>